Measuring device



5 Sheets-Sheet l Oct. 8, 1940.

u.sBERGER HBASURING DEVICE' Filad July 8, 1939 Od. 8, 1940. U s, BERGER 2,216,730

unsunms DEVIQE P1104 July 8, 1939 5 Sheets-Sheet 3 kNo/sf LEVEL /A/VE/V TOR U5. BERGER BV Oct. 8, 1940.y 1 1r s, BERGER 2,216,730

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/M/EA) TGR y U S` BERGER u. s. BERGER MzAsuRmG DEVICE Oct. 8, 1940.

5 Sheets-5heet 5 Filed July 8, 19259 /A/l/E/v 70A 5y U; 5, BERGER ATTORNEY Patented Oct. 8, 1940 UNITED STATES PATENT OFFICE MEAsUnmG DEVICE Uriah s. Berger, New York, N. Y., einer te Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 8, 1939, Serial No. 283,366

6 Claims. (Cl. 16115) This invention relates to electrical measuring relation to timewhen such signal is transmitted devices and particularly to recording means for over a mutable link; observing by numerical count the condition of Fig. 4 is a graph plotted `between rectiiled a transmission channel over a given period oi current in milliamperes against input in decigv time. bels; in other words, this is a curve plotted lbe- 3 I'he object of the invention is to determine tween the input and the output ofthe amplinerwhat percentage oi time a transmission channel detector of Fig. 2; is in a given condition. Specifically, this inven- Fig. 5 shows a pair oi' graphs plotted between I tion is useful in determining what percentage oi' decibels above noise level and percentage of time 1g time a radiochannel will transmit a given signal of the signals of ordinate value; one graph inlo at least a given level above the noise level and dicatesA data obtained during the winter and anthus help in determining the usefulness of such other graph indicates data obtained during the a radio channel for a given purpose. Where summer; and v severe fading takes place and where due to com- Fig. 6' is an alternative form of the invention u mercial limitations it is only possible to transas shown in Fig. 2. In Fig. 2 marginal relays ll mit with a given maximum power, this invenare `shown, but Fig. 6 makes use of gas-illled tion has been found useful inv determining what trigger tubes. A type oi signal can most successfully be em- A speech pathA I leads to a hybrid coil 2 from pioyed. which a path I for outgoing speech leads to a Essentially the invention comprises a denomivogad 4. The outgoing speech then passes 2o nator timer, a plurality of numerator timers, and through a transmitting Suppressor 5 and by a marginal means responsive to the condition means oi.'l an ampliiler-detector 6 operates a to be observed for controlling said numerator chain of relays Iy here labeled as voice operated timers. Such a marginal means acts as an in- Switching lCircuit. This voice operated switch- Il dicator'causing the operation of all numerator ing Circuit COnI'OlS a transmitting Singing Sup- 25 timers below the indication at any time and the pressor 9 so that the outgOing Speech can PBSS non-operation of all numerator timers above from the transmitting suppressor 5 through the such indication. The marginalmeans is capable delay and amplifier 3 and the transmitting singof faithfully and rapidly following the variains suppressor!! to the hybrid coil l0. From the U tions of the given condition as they occur.A hybrid coil i0 the speech reaches another hy- 30 A feature of the present invention is n master brid coil Il and thence goes through the radio or denominator timer and a plurality oi numertransmitter l2 t0 the transmitting antenna |3- ator timers in the form of electrically driven Through radio transmission the speech will be numerical counters such as those used as mesreceived at Some distant Point and fOr purposes sage registers in telephone working. of explanation it will be assumed that the dis- 35 Another feature 0f the invention is a martant point has 8. receiving Circuit Similar in al1 ginal means in the form o! a plurality of dlilerrespects to the lower part of Fig. 1. The speech ently adjusted electroresponsive'devices. In one therefore enters antenna Il, DHSSCS a radio respecific form of the invention such electroceiver l5 and a vodas repeater to a hybrid coil 40 responsive devices are relays. In another spe- Il. From the hybrid C011 I7 the Speech 808s into 40 eine form of the invention such eleetroresponsive hybrid coil i8. thence through the receiving sinsdevlees are gas-allen trigger action tubes. ins Suppressor I9, the receiving repeater 2.

Another feature of the invention is a visual 10W-pass filter 2| and 8' Path 22 t0 a hybrid C011, indicating means for snowing the state of the Such as 2. whence it sees to .the receiving sub- 5 condition to be observed at any instant. scriber over a line, such as i.

The drawings consist oi' five sheets containing That Part 0f the Circult between and includsix figures. ing the radio transmitter and the radio receiver Fig. 1 is a. general schematic diagram of an I5 is spoken of as a mutable link since it comlnterpolated telephone and telegraph system inprises a signaling channel capable of or liable' 50 dicating where the measuring device of the presto change from internal orexternal cause which 50 ent invention may be connected to the circuit; may give rise to interfering energy or more spe- Fig. 2 is a circuit diagram of the measuring ciflcally, subject to noise, fading orchange of device of the present invention; impedance.

Fig. 3 is a chart indicating by coordinate 'I'he voice operated switching circuit 1 controls u means how the strength of a signal may vary in a control tone enabler 23 so that a source of con- 55 trol tone 24 is passed anrough the control tone filter 25 to the hybrid coil II and thus enables speech. The voice operated switching circuit I also controls a switching point leading from the receiving switching circuit 26 at the same terminal to the transmitting suppressor 5 so as to open this circuit during the periods when speech is going out from line I to antenna I3. During this time the voice operated switching circuit I also controls the telegraph control circuit 21 to stop the action yoi the telegraph transmitting circuit.

At the receiving end the control tone coming in over antenna I4 passes through hybrid coil I1 and thence through telegraph band elimination iter 28 and into a control tone amplifier and filter 29 and thence into detector 45. This operates the relays of the receiving switching circuit 26 which performs several functions as follows: First, the circuit 26 controls a normally open circuit between the telegraph band elimination filter 28 and the detector 45 including a speech amplifier 30. This is provided so that when control tone is first received the receiving switching circuit 26 will be operated thereby and then held operated thereafter by speech currents ilowing through the amplifier 38. This means that the circuits 28 and 38 are both effective and operate in conjunction with each other to hold the receiving switching circuit chain of relays operated.

The receiving switching circuit 26 also controls the receiving singing suppressor I3 to open up the speech path. The receiving switching circuit 26 also controls a normally closed path between the band-pass iilters 2l and 48 and the telegrad 32 so that while speech is being received the telegrad 32 will be disabled. At the same time the receiving switching circuit 26 controls the switching relays for two telegraph channels 33.

During pauses in speech, either when the subscriber at the distant end is talking into channel I or during the time when the subscriber or channel I pauses during his talking out over the antenna I3, the telegraph apparatus shown in the upper part of the figure is in operation. This comprises periorators 34 and 35, working respectively into tape transmitters 36 and 31 and thence into rotary distributor 38. Rotary distributor 38 works into the control circuit 21 which in turn exercises control over the telegraph signal suppressor 39. A source of telegraph signal tone is supplied to the telegraph signal oscillator 48 and through the action of the telegraph signal suppressoi 38 under control of the control circuit sends telegraph signals into the hybrid coil I0, thence through the hybrid coil II and out over the radio transmitter I2.

At the distant end these telegraph signals in the form of spurts of alternating current are received over antenna I4 and radio receiver I5 and thence pass through the hybrid coils I1 and I8 to the band-pass filter 3I. Thereafter the signals enter the telegrad 32 and are converted from varying strength alternating current signals to uniform strength direct current signals of practically the same length at which they were received over the antenna I4.

The direct current signals produced by the telegrad 32 pass over path 15 to the switching relays 33, thence through the rotary distributor 4I to the two printers 42 and 43. During the reception of telegraph signals the receiving switching circuit 26 is unoperated and the speech path is blocked ofi by the receiving singing suppressor I9.

Line 44 schematically represents the means for keeping the rotary distributor 38 in exact synchronism with the distant rotary distributor 4I. The rotary distributor 38 and the rotary distributor 4I at the same terminal may or may not be kept in synchronism. In actual practice they ngenerally are kept in synchronism for reasons having to do with the cost of synchronizing apparatus but from an operating standpoint it is only necessary that the rotary distributor forming part of the same channel be kept in synchronism.

In Fig. l there is a circle with a letter T drawn therein with an arrow pointing to the path between the band-pass iilter 3| and teiegrad 32. This is an indication of a point to which the measuring device, subject of the present invention, may be connected. Likewise another circle with the letters TC drawn therein with an arrowhead pointing to the circuit between the control tone amplifier and lter 29 and the detector 45, is an indication of another point to which the measuring device may be connected. In the rst case, the telegraph tone from the telegraph signal oscillator 40 may be measured as it is varied by the action of the mutable link between the radio transmitter I2 and the radio receiver I5. In the second case, the control tone from the oscillator 24 may be measured as it is effected by the operation of the mutable link. In making these measurements, the system is shut down `from normal operation and if the telegraph tone is to be measured then the circuit is temporarily arranged so that telegraph tone will go out over the antenna I3 continuously for the length of time allotted for the test. In the same manner the circuit may be temporarily arranged so that the oscillator 24 sends out control tone over the antenna I3 for the duration of the test. At the distant end the measuring device is connected to the circuit at one of the points indicated.

The measuring device consists essentially of a pair of input terminals 50 leading through amplifier tubes 5I and 52 to a rectifier device consisting of four copper-oxide rectiiiers 53, 54, 5l and 56 connected in a bridge circuit. The alternate vertices of the bridge connect to seven marginal relays in series designated B to H, inclusive. Each of these relays is differently adjusted as indicated in Fig, 4. Fig. 4 is a graph showing the rectified current coming from the copper-oxide bridge plotted against the input at the terminals 50 and since all of these relays may be accurately adjusted to operate and release within a very narrow margin they may be adjusted as indicated by this curve so that relay B, for instance, operates and releases at 5 decibels above noise level, relay C operates and releases at approximately l0 decibels above noise level, D operates and releases at approximately 15 decibels above noise level, etc.

With the relays so adjusted reference should be made to Fig. 3. This is an indication of signal variation over a mutable link. The wavy line indicates the actual variation in the strength of the signal which, of course, might be measured by an oscillograph or some sensitive instrument. However, for practical purposes and to avoid the later interpretation of such a curve, the relays B to H, inclusive, are connected in the circuit as explained and will be operated during the time that their lines in Fig. 3 are shown as heavy lines.

Connected to the-back contact of each of these relays in Fig. 2 there is what may be termed a numerator timer. This may be of any nature which will give an indication o! the length of time they have been in operation. For instance, these may be in the form of ordinary telephone-type message registers and may be connected in a circuit irom an armature of a relay 51 which is caused to vibrate by a source of alternating current, for example, of 5 cycles per second. Thus if relay B, for instance, rests on its back contact for one second, the numerator timer will be caused to register a count of 5. A denominator timer 59 is connected to the back contact of relay 51 and hence operates continuously over the length of time that the measuring device is in service. v

At the end of a period of service the readings of the denominator timer 59 and the numerator timer, such as 58, are taken and through a simple arithmetical operation the percentage of time a signal is of a certain value may be obtained and plotted, for instance, in the manner of Fig. 5. This figure is a typical example of data obtained over a circuit of this nature, in the one case, during the winter and, in the second case, during the summer.

With the message register, such as 58, connected as shown in Fig. 2 the reading of the numerator timer 58 divided by the reading of the denominator timer *59 will give the percentage of time over which the signal was ineffective t operate the relay B. The connection of the message register 58 might just as well have been made to the front contact of relay B. The reading of the numerator timer 58 divided by thedenominator 59 Will then give the percentage of time over which the signal was strong enough to operate the relay B.

Connected to the front contact of relays B to H, inclusive, are lamps 60 to 6B, inclusive. These lamps will give a visual indication of the strength of the signal coming in at any particular time and thus will serve as an instantaneous indicating means.

In Fig. 6 another form of measuring device is shown. This consists essentially of a circuit having input terminal 61 which may be connected to either the point CT or T in Fig. 1. The incoming signals operate the rectier tube 68 and a voltage is developed across the resistance 69. Various taps taken 01T this resistance, each lead to a trigger tube, such as 12, and the voltage drop produces a negative potential on the grid of such gas tube 12, If no input is present on the terminals 61, no voltage will appear across the resistance 69 and hence gas tube 12 will be conducting.- The anode current of gas tube 12 Will then operate the register 13. When this register operates it closesy a contact from the front contact of relay 14, the armature and contact of register 13 to condenser 1|. Relay 14, in a manner similar to relay 51, is operated by a source of low frequency alternating current, for example, at the rate of ve alternations per second. After the register 13 has closed its armature contact then when next the relay 14 applies ground to the lead 10, the condenser 1|, which is normally charged by battery connected to common lead 16, will have its charge suddenly changed by the ground connection. This sudden change of potential on the condenser 1| causes the gas tube 12 to be extinguished and the current through the register to cease flowing However, after a short interval thefcharge on condenser 1| is equalized and thetube again becomes conductive and register 13'is again operated. Since the extinguishment of tube 12, the release of register 13 and the reoperation of this relay is faster than the pulsing of relay 14, the register 13 will follow the operation of such relay 14.

If a steady input is applied to terminals 51 the direct current potential developed across potentiometer 69 will be suiiicient to keep the gas tubes from conducting once they have been extinguished and therefore the register Will not operate when the strength of the signal is above the point at which each register, such as 12, 11 and 18, is adjusted to respond. In practice, the tube 12 will be adjusted to cease operation when the signal reaches at least decibels above noise level, the tube 11 will be adjusted to cease operation when the signal reaches the level of decibels above noise level, the tube 18 at 15 decibels above noise level, etc.

If We consider the presence of strong input as normal value of unfaded signal none of the registers will operate but ifv the potential developed across the potentiometer 69 drops through fading then one or more of the ga's tubes will be rendered conductive and a count on the corresponding numerator timers will be made.

This variation has the advantage over the variation shown in Fig. 2 in that if a very rapid decrease in signal strength through fading occurs the gas tube, such as 12, will immediately become conductive and will continue so until extinguished by relay 14. The time for ionization to take place is very short and many times faster than the operate time of the counters, such as 13. Re-

cordings of very short fades are then insured whereas the relay circuit of Fig. 2 requires the fading to vbe at least as long as the operate time of the register.

With the aid of measuring devices of this nature, data, such as that shown in the curves of Fig. 5 may be obtained and these data are extremely useful in engineering a system such as that schematically shown in Fig. 1.

What is claimed is:

1. An electrical measuring device for determining the percentage of time a given variable condition is present in an electrical circuit comprising a plurality of numerator timers each for giving a numerator reading indicating the time duringwhich a different degree of said variable condition was present in said circuit over a given denominator time, and a like plurality of circuit closing means for controlling said numerator timers, said means being each differently responsive to said condition.

2. An electrical measuring device for determining the percentage of time a'given variable condition is present in an electrical circuit comprising a plurality of numerator timers each for giving a numerator reading indicating the time during which a different degree of said variable condition was present in said circuit over a given 'denominator time, and a like plurality of marginal relays each constructed and arranged to respond to a different degree of said condition for controlling said numerator timers.

3. An electrical measuring device for determining the percentage of time a given electrical condition is present in an electrical circuit comprising a plurality of numerator timers each for giving a numerator reading indicating the time.y

mining the percentage oi' time an electrical channel is in condition to deliver a signal of various given strengths, comprising a plurality of numerfator timers each for giving a numerator reading indicating the time dui ing which a difierent strength signal was delivered over a given denominator time, and a like plurality of circuit closing means for controlling said numerator timers, each said means responding to a din'erent strength delivered signal.

5. An electrical measuring device for determining the percentage of time a given variable condition is present in an electrical circuit comprising a plurality of numerator timers each for giving a numerator reading indicating the time during which a different degree oi' said variable condition was present in said circuit over a given denominator time, a like plurality oi circuit closing means for controlling said numerator timers,

said means being each diierently responsive to said condition, and means for giving a visual indication oi' which of said circuit closing means are operated at any time.

6. An electrical measuring device for determining the percentage oi' time a given variable condition is present in an electrical circuit comprising a plurality of numerator timers each for giving a numerator reading indicating the time during which a diii'erent degree of said variable condition was present in said circuit over a given denominator time. a like plurality of marginal relays each constructed and arranged to respond to a different degree of said condition for controlling saidnumerator timers, and signal lamps operated by said relays for giving a visual indication of which relays are operated at any time.

Umax s. Banana. 

